Lead-sheathed telephone cable



E. scHtJRERl LEAD SHEATHED TELEPHONE4 CABLE sept. 11, 19m 1,684,363

Filed Nov. 2e, 191;?A

Patented Sept. 11, 1928.

uNiTIsDV STATES PATENT OFFICE.

EUGEN SCHRER, 0F COLOGNE-lYIULHEIJL GERMANY, ASSIGNOR TO FELTEN 6r GUIL- LEAUME CARLSWERK ACTIEN-GESELLSCHAFT, 0F COLOGNEJYIULHEIM, GERMANY.

LEAD-SHEATHED TELEPHONIE CABLE.

Application filed November 26, 1927, Serial No. 235,891, lam! in Germany' November 27, 1926.

It has already been proposed to surround the conductors, pairs of conductors, quads or groups of conductors of lead sheathed telephone lcables with metallic covers for reducing mutual inductive action. These metallic covers were mostly either not.con nected at all to the lead sheath or only-at the beginninlr or end of the manufactured lengths of cable, the core of the cable being separated from the lead cover by a paper or strip wrapping for protecting the conductors and covers from damage when the lead sheath -is being pressed round them. Hitherto, however, telephone,v cables with such covers have not always` shown the desired freedonfrom cross talking, more articularly when high Ydegrees of amplification are being used, as is for instance the case with cables which are used for the transmission of music. It has been found that very good results are obtained when provision is made for securing a continuous connection between the metallic covers and the lead sheath', as by this means the conductivity of the covers is effectively assisted by that of the lead sheath. In making a continuous connection of the metallic covers, however, special difficulties are met with, owing to t e fact that the covers and conductors easily become damaged when the lead sheath is being pressed round the same.

In order to avoid such damage, according to the present invention the core -of the cable consisting of conductors with electrically conductiing covers is wrapped, before,

the lead sheath is pressed round, with a. muslin band having metallic threads running through it, the use of which is known in connection with power cables. Such a muslin band embodying metallic threads both prevents the conductors being damaged when the lead sheath is being applied and ensures an intimate metallic connection between the metallic covers and the lead sheath.

Figs. 1 and 2 show in cross-section and elevation a constructional example of a telephone cable accordin to the present invention. a' are the con uctors provided with metallic covers, b the insertions for iillin up hollow spaces and c is the muslin ban having metallic threads running through it,

which is for instance Wrapped around stranded double conductors enveloped in metalized paper-.--`Over the muslin band with the metallic threads lies the lead y sheath.

lVhat I'. claim is: A telephone cable comprisino' in combination a Core containing electric conductors and electricallyy conducting covers on the said conductors, a lead sheath for the said core and a lWrapping of muslin band having metallic threads 4runnin through it between the core .and the lea for the purpose set forth.

In testimony whereof I have signed my name to this specification.

EUGEN SGHRER,

sheath, as and I 

